Dr Imran Ahmad, a clinician scientist at Cancer Research UK – which part-funded the study – said the prevalence of inherited faults exceeded previous estimations in these patients.
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While men with the more aggressive form of the cancer make up about 5% of the 180,000 to 200,000 cases of prostate cancer in the US each year, and only 12% will have these mutations, that population is still at considerably higher risk of developing advanced disease.
Their tumours were also genetically tested, and researchers tracked each patient’s cancer-related mutation in his or her blood samples in the months and years after surgery.
For years now, doctors have been able to easily identify women who have higher chances of developing breast cancer due to genetics. He is a geneticist and pediatric oncologist at Memorial Sloan Kettering (MSK) Cancer Center in New York City.
Inherited mutations in DNA-repair genes, such as the BRCA genes, can increase cancer risk.
Its OncotypeDX line of tests for breast, prostate and colon cancers gives patients with early-stage disease information on whether they’re likely to benefit from chemotherapy-or in the case of the prostate, other aggressive care-as part of their treatment. This could lead to preventive measures against the disease.
The mutations occur far more often in men with advanced disease than in those with prostate cancer that hasn’t spread, the study authors said.
The study is the largest of its kind to date, and the first to comprehensively analyse germline mutations in men with advanced, or metastatic, prostate cancer – where the disease has spread around the body.
The findings suggest that genetic screening for mutations in genes that keep the DNA error-free may benefit men with prostate cancer as screening for mutations in DNA-repair genes may help them get better treatments and alert their family members of their own cancer risks. But Offit and study’s other researchers believed that the new findings are enough to urge for a change in clinical guidelines.
The recent drugs are most used in patients suffering from ovarian cancer, yet the medicine has to be proven to be very effective in patients suffering from prostate cancer and having the DNA-repairing genes.
“In the future, this could help doctors decide which treatments to offer patients with a positive blood test result, and potentially save those who test negative from extra treatment and side-effects”, added Professor Shaw.
Qiagen NV of Germany and Tokai Pharmaceuticals Inc., Boston, are codeveloping an AR-V7 liquid biopsy test based on different technology as a diagnostic test for Tokai’s experimental prostate-cancer drug called galeterone meant to treat men who test positive for AR-V7. Nelson also mentioned about platinum-based chemotherapy that also being used for ovarian cancer could benefit advanced prostate cancer patients.
The frequency of germline mutations in men with prostate cancer – which did not differ according to age at diagnosis or family history of prostate cancer – suggests a need for routine genetic testing in this population.
With the exception of some cancer syndromes in children, prostate cancer is the most heritable of human malignancies.
But he cautioned that it was still early days – more studies are needed to assess this.
Now no DNA-based blood tests for cancer are FDA approved. SU2C is a program of the Entertainment Industry Foundation whose scientific partner is the American Association for Cancer Research.
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Besides Memorial Sloan Kettering and Fred Hutchinson, other institutions involved in the study were the University of Washington School of Medicine, University of Michigan, Dana-Farber Cancer Institute, Weill Cornell Medical College and the Institute of Cancer Research and Royal Marsden Hospital in London.
